Add username check and try/catch block

Author: sadortun

spec/ParseLiveQuery.spec.js

@@ -667,6 +667,7 @@ describe('ParseLiveQuery', function () {
     Parse.Cloud.beforeUnsubscribe(TestObject, req => {
       expect(req.requestId).toBe(1);
       expect(req.user).toBeDefined();
+      expect(req.user.get('username')).toBe('username');
       done();
     });
 

src/LiveQuery/ParseLiveQueryServer.js

@@ -852,7 +852,15 @@ class ParseLiveQueryServer {
       request.useMasterKey = client.hasMasterKey;
       request.installationId = client.installationId;
 
-      await runTrigger(trigger, `beforeUnsubscribe.${className}`, request, auth);
+      try {
+        await runTrigger(trigger, `beforeUnsubscribe.${className}`, request, auth);
+      } catch (error) {
+        Client.pushError(parseWebsocket, error.code || 141, error.message || error, false);
+        logger.error(
+          `Failed running beforeUnsubscribe for session ${request.sessionToken} with:\n Error: ` +
+            JSON.stringify(error)
+        );
+      }
     }
 
     // Remove subscription from client

src/cloud-code/Parse.Cloud.js

@@ -703,7 +703,7 @@ ParseCloud.onLiveQueryEvent = function (handler) {
  */
 ParseCloud.beforeUnsubscribe = function (parseClass, handler, validationHandler) {
   validateValidator(validationHandler);
-  var className = getClassName(parseClass);
+  const className = getClassName(parseClass);
   triggers.addTrigger(
     triggers.Types.beforeUnsubscribe,
     className,